star-erp/app/Modules/Inventory/Models/InventoryTransaction.php

<?php

namespace App\Modules\Inventory\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use App\Modules\Core\Models\User; // 跨模組核心依賴

class InventoryTransaction extends Model
{
    /** @use HasFactory<\Database\Factories\InventoryTransactionFactory> */
    use HasFactory;

    protected $fillable = [
        'inventory_id',
        'type',
        'quantity',
        'unit_cost',
        'balance_before',
        'balance_after',
        'reason',
        'reference_type',
        'reference_id',
        'user_id',
        'actual_time',
    ];

    protected $casts = [
        'actual_time' => 'datetime',
        'unit_cost' => 'decimal:4',
    ];

    public function inventory(): \Illuminate\Database\Eloquent\Relations\BelongsTo
    {
        return $this->belongsTo(Inventory::class);
    }

    public function user(): \Illuminate\Database\Eloquent\Relations\BelongsTo
    {
        return $this->belongsTo(User::class);
    }

    public function reference(): \Illuminate\Database\Eloquent\Relations\MorphTo
    {
        return $this->morphTo();
    }
}